In a pneumatic tire for a construction vehicle, mounted on a construction vehicle or the like such as a dump truck for use in a construction site or a mine, tire wear life thereof is generally prolonged, i.e. wear resistance thereof is improved, by increasing a volume of tread rubber and/or reducing an area of groove portions formed in a ground contact surface of a tread portion thereof. However, the tire of this kind having a large volume of tread rubber of itself inevitably experiences an increase in temperature at the interior of the tread portion and thus thermal degradation of rubber by the increase in volume of tread rubber and/or the decrease in groove area in the ground contact surface of the tread, which may eventually cause troubles in the tire.
In view of this, there has been developed for such a tire as described above a technique of suppressing an increase in temperature of a tread portion, with maintaining high wear resistance at a ground contact surface of the tread portion, as disclosed in PTL 1. However, further suppression of an increase in temperature of a tread portion is demanded in recent years because such a tire as described above is increasingly used for a construction vehicle or the like which runs at higher speed.